chorus/CHORUS-PLAN.md

CHORUS — Group-Based Memory: Conversion Plan

Fork of: jason/echo (ECHO v1.5.1, schema 4) → jason/chorus Goal: convert the single-operator ECHO memory plugin into CHORUS — one shared Obsidian vault serving a group of members, with per-member identity, attribution, and isolation of the churn-prone per-person state, while keeping the shared knowledge graph (projects, areas, resources, decisions) communal.

Naming metaphor: ECHO is one voice reflected back; CHORUS is many voices in one performance.

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1. What the review found

ECHO is ~4,800 LOC of pure-stdlib Python (18 scripts) + a large doc surface (SKILL.md ~456 lines, 6 references, 8 commands, 15 scaffold seeds). The architecture is already favorable for this conversion:

• Identity is barely wired in. echo.py loads OWNER from config but never actually consumes it — attribution today is purely doc-driven ("write in third person about Jason"). Adding a member identity breaks nothing.
• Routing is data-driven. routing.json is the single source of truth for "what may be written where"; vault_lint.py and check_routing.py enforce it. Per-member paths are new route rows, not new code paths.
• The vault is self-describing. Bootstrap/migrate/sweep + schema_version in the marker give us a clean upgrade lever (schema 4 → 5).

The hard part is not identity plumbing — it's the five shared single-writer artifacts that make no sense (or clobber) with multiple concurrent users:

Artifact	Today	Problem in a group
_agent/memory/semantic/operator-preferences.md	One profile	Whose preferences?
_agent/context/current-context.md	One active scope for the vault	Members work on different things simultaneously
_agent/heartbeat/last-session.md	One "last session" pointer (PUT overwrite)	Race: lost updates; meaningless shared
inbox/captures/inbox.md	One shared inbox (POST append)	Append races; triage can't tell whose capture
journal/daily/YYYY-MM-DD.md ## Agent Log	One shared heading	Duplicate-heading races; unattributed lines

Also single-user by design: session filenames carry no author (YYYY-MM-DD-HHMM-<slug>.md — two members can collide on the same minute), frontmatter has no author: field anywhere, the offline queue is per-machine with no member attribution, and the advisory lock owner is a session id, not a person. Concurrency is advisory-only — vault_lock() warns and proceeds if it can't acquire (echo_concurrency.py:78–81), which is acceptable for one person on two machines but not for N people.

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2. Target design

2.1 Identity model

• Config gains a member field: { "group": "...", "member": "jason", "endpoint": "https://chorusapi.mpm.to", "key": "..." }. Deployment endpoint: https://chorusapi.mpm.to — the CHORUS vault gets its own Obsidian + Local REST API instance exposed there (separate from ECHO's echoapi.alwisp.com; the personal ECHO vault is untouched). The endpoint stays machine-local/baked config, never in source, same as ECHO. owner → group. Resolution order unchanged: baked > env (CHORUS_MEMBER etc.) > config file. Baked per-user builds (build.py --bake-key --label alice) already exist and become the primary onboarding mechanism: one artifact per member, member id baked in.
• Every agent-written note gets author: <member> stamped in frontmatter (echo_ops._build_note), added to the canonical frontmatter block, to KIND_REQUIRED_FM for agent-written kinds, linted by vault_lint, and backfilled by sweep --apply (existing notes → the migrating member).
• Lock owner and offline-queue entries carry the member id (auto_owner() → f"{member}-{client}-{pid}"), so contention and replay are attributable.

Auth reality check: the Obsidian Local REST API has one bearer key per vault. Phase 1–4 ship with a shared key and honor-system attribution (fine for a trusted team). Real per-member credentials/revocation would need a thin auth proxy in front of chorusapi.mpm.to that maps per-member tokens → the vault key and can inject/verify the member id. That's deliberately out of scope here but the config shape (member + per-member baked artifacts) is designed so the proxy slots in later without another migration.

2.2 Vault layout changes (schema 5)

Per-member state moves under a member namespace; shared knowledge stays where it is.

_agent/
├── chorus-vault.md            ← renamed marker (schema_version: 5, managed_by: chorus-memory-plugin)
├── members/
│   └── <member>/
│       ├── preferences.md     ← was operator-preferences.md (one per member)
│       ├── current-context.md ← per-member scope + Scope History
│       ├── heartbeat.md       ← per-member last-session pointer
│       └── inbox.md           ← per-member quick-capture inbox
├── memory/
│   └── semantic/
│       └── group-profile.md   ← NEW: shared facts about the group itself
├── sessions/
│   └── <member>/YYYY-MM-DD-HHMM-<slug>.md   ← member-namespaced session logs
└── (context/, memory/, health/, index/, locks/, templates/, skills/ unchanged — shared)

• Shared and unchanged: projects/, areas/, resources/, decisions/, journal/, semantic/episodic/working memory (now with author:), the entity index, recall index, health notes.
• Daily Agent Log stays one shared heading (it's the group's timeline) but every line is member-prefixed: - HH:MM [alice] did X. ensure_daily_log keeps its GET→POST-heading→PATCH flow; idempotent whole-line append plus the member prefix makes interleaving safe and attributed. (Per-member daily notes were considered and rejected — the whole point of a group vault is one shared timeline.)
• Inbox: per-member capture files (_agent/members/<id>/inbox.md) kill the append race and make triage member-aware, plus one shared inbox/captures/group.md for unowned "someone should look at this" items (member-prefixed lines; routed by whoever triages first). Triage covers both: accepted items route to shared homes; preference-type items route to that member's preferences.md. Processing-log lines carry the member id.
• resources/people/<member>.md continues to exist for every member — the public "who is this person" note, distinct from their private-ish preferences.md (how the agent should behave for them).

2.3 Cold-start load (per member)

chorus.py load reads: marker → group-profile → my preferences → my current-context → my heartbeat/last-session (fallback: my sessions dir) → today's shared daily note → my inbox depth → group inbox depth. Optional --all-members flag for a group-wide orientation (e.g., "what has the team been doing"). Reconcile (inbox aging, scope drift) runs against the member's own state only.

2.4 Concurrency posture

Namespacing removes ~all of the contention (each member's churn-prone files are theirs alone). What remains shared-write:

• Entity + recall indexes — keep vault_lock + atomic_index_update, but flip the lock to required (required=True) on index writes: block/retry briefly instead of warn-and-proceed. TTL reclaim unchanged.
• Daily note / shared notes — idempotent member-prefixed appends; PATCH to headings is last-writer-wins per line, which is acceptable for log lines.
• Duplicate gate — unchanged and global (dedup across the group is the feature: two members shouldn't create parallel notes for the same client). Gate messages name the author of the existing candidate.

2.5 Recall / reflection

• Corpus unchanged (shared graph is the point). recall gains an optional --author <member> filter and surfaces author: in hits.
• reflect proposals route preference items to the current member's preferences.md; everything else routes to shared homes with author: stamped. The Stop-hook nudge state stays per-machine (already is).

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3. Renaming map (echo → chorus)

Category	From	To
Plugin	echo-memory (plugin.json, skill dir, SKILL.md name)	chorus-memory
Commands	/echo-{load,save,recall,reflect,triage,sweep,health,doctor}	/chorus-*
Scripts	echo*.py (16 modules + imports everywhere)	chorus*.py
Exception	EchoError	ChorusError
Env vars	ECHO_OWNER/BASE/KEY/CONFIG/TODAY/VERIFY/LOCK_TTL/TIMEOUT/WORKERS/STATE_DIR/CLIENT/DUP_GATE/REFLECT_MIN_TURNS/FRESH_HALF_LIFE	CHORUS_* (+ new CHORUS_MEMBER)
Config file	~/.claude/echo-memory/config.json	~/.claude/chorus-memory/config.json
State dir	~/.echo-memory/	~/.chorus-memory/
Marker	_agent/echo-vault.md (hardcoded in 8 files + routing.json)	_agent/chorus-vault.md
Hooks	hooks.json paths ×2 incl. CoWork fallback glob	updated paths
Docs/branding	README, SKILL.md, references, scaffold seeds, icons	rewrite pass (cosmetic but large)

operator-preferences.md is renamed as part of the layout change (§2.2), not the branding pass.

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4. Phased plan

Phase 0 — Baseline (½ day)

Repo hygiene on the fork: strip stale versioned .plugin artifacts from the tree (move to Gitea releases per ROADMAP-2.0), confirm eval/ suites green as-is, tag the fork point.

Phase 1 — Mechanical rename (1–2 days) — DONE

Everything in §3. All existing tests pass under the new names. No behavior change. Deliverable: installable chorus-memory plugin that is ECHO-with-a-new-name. (Decided post-Phase-1: CHORUS is a clean break — fresh vaults on fresh machines for new users, so no ECHO back-compat: legacy ECHO_* env vars, echo-memory configs, ~/.echo-memory state, and _agent/echo-vault.md markers are all ignored. Shims briefly existed and were removed.)

Phase 2 — Identity plumbing (1–2 days)

member in config (+ CHORUS_MEMBER, baked-tier support, config set --member), MEMBER global in chorus.py, author: stamping in _build_note, canonical frontmatter + KIND_REQUIRED_FM + lint + sweep backfill, member-aware lock owner and queue entries, doctor reports resolved member. Vault layout untouched. Deliverable: every new write is attributed; single-user behavior otherwise identical.

Phase 3 — Per-member namespacing (3–5 days — the core)

Schema 5. New LEAVES + seeds (members/<id>/…, group-profile.md), member-parameterized bootstrap (bootstraps your member subtree on first load if the vault exists but your namespace doesn't — new members self-onboard), cmd_load/cmd_scope/heartbeat/inbox/triage/reflect retargeted to member paths, session logs under sessions/<member>/, member-prefixed Agent Log lines, routing.json route rows (with <member> pattern segment) + retired old paths, lint updates, migrate.py 4→5 (for any alpha CHORUS vaults stood up between phases — there is no ECHO-vault adoption path; CHORUS vaults start fresh). Docs: vault-layout.md, routing-map.md, bootstrap.md rewritten. Deliverable: a real multi-member vault, bootstrapped from empty.

Phase 4 — Shared-write hardening (1–2 days)

Required lock on index writes with bounded retry/backoff, gate messages carry author, recall --author, load --all-members, concurrency docs (operating-contract.md) rewritten for N writers.

Phase 5 — Docs, onboarding & eval (2–3 days)

SKILL.md full rewrite (operator → member voice; drop the "single owner" safety rule, replace with group rules: don't edit another member's preferences.md except via their session; shared notes are fair game), 8 command docs, README. Onboarding runbook: per-member baked builds. Extend eval/: two-member mock scenarios (concurrent capture, interleaved daily-log appends, index race, cross-member dedup gate, member-scoped load) + rerun the retrieval/durability metrics. New icon.

Total: roughly 9–15 working days, shippable at every phase boundary (1 = rename, 2 = attribution, 3 = groups).

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5. Decisions (settled with Jason, 2026-07-21)

1. Journal rollups — shared. One group rollup per period (journal/weekly/YYYY-Www.md etc.) with member-attributed bullets inside. No per-member rollup trees.
2. Preference privacy — group-visible, documented. Member preferences.md files live in the shared vault and are readable by every member (one vault, one key — no read ACLs possible). SKILL.md documents this explicitly; anything a member considers private belongs in their own personal ECHO vault, not CHORUS.
3. Auth proxy — out of scope; shared key first. Phases 1–5 ship with the shared vault key and honor-system attribution. The per-member token proxy (namespace write ACL, server-side audit, per-member revocation) is a later standalone project; the config shape (member + per-member baked artifacts) already accommodates it with zero plugin changes.
4. Commands — /chorus-*. Full-prefix names (/chorus-load, /chorus-save, …), consistent with the ECHO pattern and collision-free if both plugins are installed.
5. Inboxes — per-member + shared group inbox. Each member gets _agent/members/<id>/inbox.md; a shared inbox/captures/group.md holds unowned items (member-prefixed lines, idempotent appends), routed by whoever triages first. Both are probed at load and covered by triage.
6. Clean break from ECHO (added post-Phase-1). CHORUS vaults are fresh vaults on fresh machines for new users — no ECHO adoption path, no legacy ECHO_* env/config/state/marker compatibility. Jason's personal ECHO vault continues unchanged on its own plugin and endpoint. If ECHO history is ever wanted in CHORUS, it would be a one-off import exercise, out of scope.